The contributions of lean tissue mass and fat mass to bone geometric adaptation at the femoral neck in Chinese overweight adults

Background: Overweight or obese populations may have lower risk of osteoporotic fractures and higher bone mineral density (BMD), while bone strength is determined not only by bone material but also by bone structural parameters. Thus, the influence of body weight on bone geometry was examined in Chinese overweight adults.

Aim: The purpose of this study was to explore how total body lean mass (TBLM) and total body fat mass (TBFM) contribute to the variation of bone geometry at the femoral neck in Chinese overweight adults.

Subjects and methods: Bone geometric parameters including section modulus (Z), cross-sectional area (CSA), subperiosteal width (W), cortical thickness (CT) and buckling ratio (BR) were compared in 100 overweight (body mass index, BMI?≥?23) vs. 100 underweight subjects (BMI?≤?18.5) in Chinese female and male adults aged 20–44 years by multiple regression analyses.

Results: Multiple regression analysis revealed that both TBLM and TBFM were significantly higher in overweight subjects than in underweight subjects. Meanwhile, significant differences in bone geometric parameters (except W) were also detected between the overweight and underweight groups after adjustment for age and height in both sexes (p?≤?0.001). Bone bending strength Z and axial strength CSA were 14% and 13% higher in females, as well as 18% and 20% higher in males in the overweight group than in the underweight group, respectively. The significant differences mentioned above were not observed when adjusted for TBLM, age, and height. TBLM seemed to be the strongest significant positive predictor of bone geometric parameters (p?<?0.001), with the exception of W in both sexes and BR in females, while TBFM did not contribute significantly to the bone geometric parameters (p?>?0.055 for both sexes).

Conclusion: Bone geometry may adapt primarily to mechanical load as represented by TBLM, but TBFM seemed to have no independent effect on bone geometry in Chinese overweight subjects.     

Bone mineral density in older non-Hispanic Caucasian and Mexican-American women: relationship to lean and fat mass

Primary objective: The prevalence of osteoporotic fracture is higher in non-Hispanic Caucasian (NHC) than Mexican-American (MA) women in the USA. The present study examined bone mineral density (BMD) in these two ethnic groups and the association between BMD and body composition.

Research design: Cross-sectional.

Subjects: Sixty-two NHC and 54 MA women, aged 60-86 years, with a body mass index (kgm^-2) of &lt; 30.

Methods: BMD (gcm^-2) of the spine (L_2-4), hip (femoral neck, trochanter, Ward's triangle) and whole body was determined by dual-energy X-ray absorptiometry (DXA). Bone mineral-free lean mass (LM) and fat mass (FM) and several ratios of body fat distribution were also assessed by DXA.

Results: There was no difference in age (NHC, 69.5 ± 0.7; MA 69.5 ± 0.9 years; mean ± SEM) or body mass, but MA women were shorter with a higher truncal adiposity (p < 0.001). There was no significant difference in BMD between groups, however, adjusting for height resulted in higher hip and whole body BMD in MA women (p < 0.01). When volumetric bone density was calculated (bone mineral apparent density; BMAD, g cm^?3), a trend for higher values in MA women was observed at the femoral neck (p = 0.018). LM contributed independently to BMD at the spine and hip in NHC women, with FM also contributing at the femoral neck. In MA women, LM was an independent contributor to lumbar spine and trochanter BMD, and both LM and FM contributed to whole body BMD. However, the effects of LM and FM were removed in both groups when BMD was adjusted for body or bone size, the only exception being at the trochanter in NHC women.

Conclusions: These results indicate that MA women have higher bone density at the proximal femur than NHC women, which may partially account for their lower rate of hip fracture. Further, differences in bone density between the two ethnic groups do not appear to be dependent on soft-tissue composition.     

Association between bone,body composition and strength in premenarcheal girls and postmenopausal women

Aim: The study examined whether associations between bone, body composition and strength are age dependent.

Subjects and methods: Two age levels (premenarcheal girls and postmenopausal women on HRT) were studied in a 10-month follow-up. Bone, lean and fat mass were measured by dual-energy X-ray absorptiometry (DXA), and strength was measured using an isokinetic dynamometer.

Results: In girls, significant correlations were found between mass (lean, fat and body mass), strength and most bone characteristics (r = 0.15–0.93). At the proximal femur changes in bone mineral density (BMD) were moderately related to changes in body composition. In the women, body mass and lean mass were significantly correlated with most bone characteristics (r = 0.34–0.82). Low to moderate correlations were observed between changes in bone and changes in body composition. After controlling for lean mass the relation between strength and bone was no longer significant.

Conclusions: In premenarcheal girls, bone is partly determined by mass, with lean mass the most important predictor at the femoral sites. In postmenopausal women, lean mass is an important determinant of bone mineral content (BMC) and BMD, but changes in BMD are related to changes in fat. The relation between strength and BMD is mainly attributable to the relation between lean mass and BMD. The contributory effects of soft tissue to bone change over different life periods.     

Bone status in elite male runners

The aim of our study was to compare long distance runners to body mass index (BMI)- and age-matched healthy controls with respect to bone parameters at all relevant loaded and nonloaded skeletal sites. Furthermore, we assessed the effect of running volume on bone parameters. Twenty elite male runners (21.1 km<1:15 h; volume >75 km/week/year) participated in the study (RG), 11 age- and BMI-matched male subjects (28±5 years) served as nontraining controls (CG). Subjects with any medication or illness affecting bone metabolism or with a family history of osteoporosis were not included. Bone parameters at various sites (total body, lumbar spine, femoral neck/hip, calcaneus) were measured by dual energy X-ray (DXA), quantitative computed tomography and quantitative ultrasound. Body composition was assessed via DXA and bioimpedance analysis; nutritional parameters were determined by 5-day dietary protocols. Training variables were assessed by questionnaires. Compared with nontraining controls runners had significantly higher BMD at all loaded sites (calcaneus, lower limbs, femoral neck, pelvis, and trabecular lumbar spine). BMD at nonloaded sites (ribs, upper limbs, and skull) was slightly but not significantly higher in the runners. We observed a low (r=0.30), nonsignificant association between training volume (km/week/year) and trabecular BMD of the femoral neck, which disappeared after adjusting for age, BMI, and body fat in this group of highly trained male runners. The effect of long distance running per se on bone parameters is not deleterious.     

Lower calcaneal bone mineral density and broadband ultrasonic attenuation,but not speed of sound,in South Asian than white European women

Background: Quantitative ultrasound (QUS) measures of bone predict fracture risk in older white women. South Asian women have low bone mineral density (BMD), perhaps related to smaller body size or vitamin D insufficiency, but it is unknown whether this is accompanied by lower QUS.

Aim: The study compared QUS, BMD and vitamin D status between South Asian and white European women.

Subjects and methods: Participants were 47 postmenopausal women (23 white European, 24 South Asian) aged 55–65 years. BMD was measured at the calcaneus and radius by dual X-ray absorptiometry. The QUS measurements were broadband ultrasound attenuation (BUA) at the calcaneus and speed of sound (SOS) at the calcaneus, radius and tibia. Serum 25-hydroxy vitamin D was determined in late summer.

Results: South Asian women had significantly lower serum 25-hydroxyvitamin D than white Europeans (13.0 ± 5.1 versus 30.3 ± 7.1 ng mL^–1; p < 0.001). Calcaneal BMD and BUA were 14% and 10% lower (p = 0.016 and 0.045), respectively, in South Asian women. Radial BMD, and SOS at all sites, did not differ significantly between groups.

Conclusion: In this study, postmenopausal South Asian women living in the UK had a high prevalence of vitamin D insufficiency and lower calcaneal BMD than white European women, consistent with previous findings. Differences were detected in calcaneal BUA but not SOS. Further research is needed to evaluate fracture risk and its detection in South Asian women.     

Bone mineral density in older non-Hispanic Caucasian and Mexican-American women: relationship to lean and fat mass

PRIMARY OBJECTIVE: The prevalence of osteoporotic fracture is higher in non-Hispanic Caucasian (NHC) than Mexican-American (MA) women in the USA. The present study examined bone mineral density (BMD) in these two ethnic groups and the association between BMD and body composition. RESEARCH DESIGN: Cross-sectional. SUBJECTS: Sixty-two NHC and 54 MA women, aged 60-86 years, with a body mass index (kgm(-2)) of <30. METHODS: BMD (gcm(-2)) of the spine (L2-4), hip (femoral neck, trochanter, Ward's triangle) and whole body was determined by dual-energy X-ray absorptiometry (DXA). Bone mineral-free lean mass (LM) and fat mass (FM) and several ratios of body fat distribution were also assessed by DXA. RESULTS: There was no difference in age (NHC, 69.5+/-0.7; MA 69.5+/-0.9 years; mean +/- SEM) or body mass, but MA women were shorter with a higher truncal adiposity (p < 0.001). There was no significant difference in BMD between groups, however, adjusting for height resulted in higher hip and whole body BMD in MA women (p < 0.01). When volumetric bone density was calculated (bone mineral apparent density; BMAD, gcm(-3)), a trend for higher values in MA women was observed at the femoral neck (p = 0.018). LM contributed independently to BMD at the spine and hip in NHC women, with FM also contributing at the femoral neck. In MA women, LM was an independent contributor to lumbar spine and trochanter BMD, and both LM and FM contributed to whole body BMD. However, the effects of LM and FM were removed in both groups when BMD was adjusted for body or bone size, the only exception being at the trochanter in NHC women. CONCLUSIONS: These results indicate that MA women have higher bone density at the proximal femur than NHC women, which may partially account for their lower rate of hip fracture. Further, differences in bone density between the two ethnic groups do not appear to be dependent on soft-tissue composition.     

Relationship between estrogen use and musculoskeletal function in postmenopausal women

OBJECTIVES: The purpose of this study was to examine the relationship between estrogen use and muscle strength, bone mineral density (BMD), and body composition variables in postmenopausal women. Forty healthy, untrained women participated in this study. Subjects (53-65 years) were > or =5 years postmenopausal and were categorized into either estrogen replacement therapy (ERT n=20) or non-estrogen replacement therapy (Non-ERT n=20) groups. METHODS: Muscular strength was measured by 1-RM testing using Cybex isotonic weight machines. Handgrip strength was measured using a handgrip dynamometer. Diagnostic Ultrasound was used to determine cross-sectional areas of the biceps brachii and rectus femoris muscle groups. BMD of the lumbar spine, proximal femur, and total body was assessed by Dual Energy X-Ray Absorptiometry (Lunar DPX-IQ). Body composition variables were obtained from the total body scan. Serum osteocalcin was measured as an indicator of bone remodeling. RESULTS: There were no significant differences (P>0.05) for isotonic muscular strength, muscle cross-sectional areas, handgrip strength, or percent fat between ERT and Non-ERT groups. ERT had significantly higher (P<0.05) BMD for the total body, femoral neck and Ward's Area. There were moderate positive relationships between lean body mass and the hip sites (r=0.61-0.70, P<0.05). Regression analyses determined that lean body mass was the strongest predictor of the hip BMD sites. Estrogen use also was a significant predictor for the femoral neck and Ward's Area sites. CONCLUSION: Women taking estrogen exhibited similar muscular strength, muscle size, and body composition as their estrogen-deficient counterparts. Estrogen use was also associated with higher BMD for the total body and hip sites. Generally, body composition, specifically lean body mass, influenced hip BMD more than muscular strength or estrogen use.     

Differential skeletal impact of tenofovir disoproxil fumarate in young versus old HIV-infected adults

Background:

Lower peak bone mass in early adulthood predicts subsequent fragility fractures. Antiretroviral toxicity could contribute to young HIV-infected individuals not achieving adequate peak bone mass.

Objective:

To determine if tenofovir disoproxil fumarate's (TDF) effect on bone mineral density (BMD) differs by age.

Methods:

We examined BMD data at the lumbar spine and hip from AIDS Clinical Trials Group (ACTG) A5224s and ASSERT and randomized treatment-naive studies comparing TDF/emtricitabine versus abacavir/lamivudine (with efavirenz or atazanavir/ritonavir). In this post hoc analysis, we defined the TDF effect as the difference between mean 48-week BMD per cent changes for lumbar spine and hip in individuals randomized to TDF versus abacavir. We used multivariable linear regression to compare the TDF effect in individuals younger and older than 30 years. If TDF effect by age did not differ significantly between studies, we pooled study populations. Otherwise, analyses were conducted separately within each study population.

Results:

Among 652 subjects, 21% were below age 30 years. The relationship between age and TDF effect significantly differed between A5224s and ASSERT (P?=?0.008 for lumbar spine; P?=?0.007 for hip). In A5224s, there was more bone loss with TDF at lumbar spine and hip in subjects under 30 years old versus in older subjects (???4.5% vs ??1.4%; P?=?0.045; ??4.3% vs ??1.6%; P?=?0.026, respectively). There was no significant evidence for this age-associated TDF effect in ASSERT.

Conclusions:

There was heterogeneity in the observed effect of TDF on bone density in young adults compared to older adults, suggesting that further investigation is required to understand the impact of age on BMD decline with TDF.     

The contributions of lean tissue mass and fat mass to bone geometric adaptation at the femoral neck in Chinese overweight adults

BACKGROUND: Overweight or obese populations may have lower risk of osteoporotic fractures and higher bone mineral density (BMD), while bone strength is determined not only by bone material but also by bone structural parameters. Thus, the influence of body weight on bone geometry was examined in Chinese overweight adults. AIM: The purpose of this study was to explore how total body lean mass (TBLM) and total body fat mass (TBFM) contribute to the variation of bone geometry at the femoral neck in Chinese overweight adults. Subjects and methods: Bone geometric parameters including section modulus (Z), cross-sectional area (CSA), subperiosteal width (W), cortical thickness (CT) and buckling ratio (BR) were compared in 100 overweight (body mass index, BMI >/= 23) vs. 100 underweight subjects (BMI 0.055 for both sexes). CONCLUSION: Bone geometry may adapt primarily to mechanical load as represented by TBLM, but TBFM seemed to have no independent effect on bone geometry in Chinese overweight subjects.     

Avoiding the under-diagnosis of low bone mineral density in Egyptian children with chronic medical conditions affecting bone health

Introduction

The International Society for Clinical Densitometry recommended that the lumbar spine and total body less head (TBLH) are the most accurate and reproducible skeletal sites for performing areal bone mineral density (BMD) measurements. Our objective is to evaluate the role of measurement of femoral neck BMD in avoiding the under-diagnosis of low BMD being a risk for fractures in subjects with chronic medical conditions that might affect bone health.

Material and methods

Subjects with chronic medical conditions that might affect bone health were studied (n = 468) and 36 healthy children were recruited as control subjects. Physical examinations, height, weight measurements and BMI were calculated. Dual-energy radiographic absorptiometry of the lumbar spine and femoral neck were measured.

Results

Bone mineral density z scores in both sites were significantly reduced in chronic patients, compared with control subjects. Prevalence of very low BMD z scores (–2 or more) using lumbar DXA, femoral DXA, and either of the sites were 1.38%, 3.37%, and 3.96%, respectively, while low BMD Z scores (–1 to less than –2) were 9.52%, 18.05% and 21.14% respectively.

Conclusions

We identified a significant decrease in both lumbar and femoral BMDs in studied children. Sometimes femoral BMD is decreased while lumbar BMD is still within the normal range. For this reason we recommend that, when technically feasible and there is no facility to measure TBLH, all those patients should have lumbar spine and femoral neck bone mineral density measurements to avoid under-diagnosis of low BMD being a risk for fractures.     

Bone mass preservation with high-dose cholecalciferol and dietary calcium in HIV patients following antiretroviral therapy. Is it possible?

Objective: To evaluate whether treatment with 100,000?IU/month (equivalent to 3200?IU/day) of cholecalciferol and 1?g/day of dietary calcium supplementation in HIV patients following different cART regimens yields normal levels of vitamin D3 and PTH as well as whether changes in bone mineral density are clinically significant.

Methods: Consecutive HIV patients following different cART regimens received 100,000?IU/month (equivalent to 3200?IU/day) of cholecalciferol and 1?g/day of dietary calcium supplementation. The participants underwent BMD assessment via dual energy X-ray absorptiometry of the spine and hip at baseline (T0) and after 24 months (T1). Levels of 25(OH) vitamin D3 and parathyroid hormone (PTH) were assessed at T0 and T1. Quantitative variables were assessed with a paired t-test, independent t-test or analysis of variance, as appropriate. A chi-squared analysis was used to assess the association between qualitative variables. A p-value <0.05 was considered significant. Patients were divided into three groups depending on the cART regimen.

Results: A total of 79 patients were included (40 males, 51% and 39 females, 49%), with a mean age of 46.6 (SD ±11.2) years, a baseline CD4 count of 649 cells/µl and a mean 25 hydroxycholecalciferol (25(OH) D3) value of 25?+?10?ng/ml. After 24 months, the 25(OH) D3 increased to 40?+?11?ng/ml. The initial BMDs at T0 were estimated as 0.919 (±0.27) and 0.867 (±0.14) g/cm² at the spine and hip, respectively. After 24 months, the BMD was 0.933 (±0.15) g/cm² at the spine and 0.857 (±0.14) g/cm² at the hip. Based on a BMD change exceeding 3%, a worsening was observed in 23% of patients at the spine and 27% at the hip, whereas stability or improvement was demonstrated in 77% of patients at the spine and 73% at the hip.

Subgrouping patients based on antiretroviral therapy indicated that, at T1, there was a statistically significant increase in vitamin D3 concentration in all patients, while PTH concentration was not significantly reduced in patients taking tenofovir or efavirenz. BMD stability or improvement was demonstrated in 77% of patients at the spine and 73% at the hip after 24 months.

The multivariate analysis confirms a decrease in vitamin D3 and an increase in PTH levels in smokers, as well higher vitamin D3 concentrations in males and lower spine BMDs in menopausal females.

Conclusion: The proposed protocol of cholecalciferol and dietary calcium supplementation is safe and valid for correcting vitamin D abnormalities in almost all patients as well as reducing PTH levels in a high percentage of patients; however, it is not sufficient for normalization, particularly in patients exposed to tenofovir or efavirenz. At the spine, no significant BMD change was found in any of the therapy groups. At the hip, our data confirm a modest negative effect on bone mass caused by tenofovir and efavirenz.     

Book review of Child and adolescent obesity: Causes and consequences,prevention and management. Edited by W. Burniat,T. J. Cole,I. Lissau and E. M. E. Poskitt. (Cambridge University Press,Cambridge, 2002). [pp. 436]. ISBN: 0521 652375. £70.00 hbk.

Background: Bone mineral density (BMD), bone mineral content (BMC), and bone size have been widely studied individually as important risk factors for osteoporotic fracture, but little is known about the correlation and the degree of sharing genetic and environmental factors between the pairs of the three phenotypes.

Aim: The study investigated genetic correlation (ρ_G), environmental correlation (ρ_E) and phenotypic correlation (ρ_P) between BMD, BMC and bone size.

Subjects and methods: Bivariate variance decomposition analyses were performed in 904 subjects from 287 Chinese nuclear families.

Results: Significant ρ_E, ρ_G and ρ_P were detected between BMD, BMC and bone size, except for ρ_E between BMD and bone size at the hip (ρ_E?=?0.121, p?=?0.361). Common shared genetic factors explained 86.1% and 60% of BMD and BMC genetic variations at the spine and hip, respectively. However, the genetic and environmental correlations between BMD and bone size were limited. ρ_E and ρ_G at the spine were 0.392 and 0.381, and at the hip were 0.121 and ?0.205, respectively. Only 14.5% and 4.2% of variations between BMD and bone size at the spine and hip may be due to the shared genetic factors.

Conclusion: The obtained results suggested that bone size may be used as another surrogate phenotype independently of BMD for eventual elucidation of the pathogenesis of osteoporosis because of the limited correlations between BMD and bone size.

Résumé. Arrière plan: La densité minérale osseuse (DMO), le contenu minéral de l’os (CMO) et la taille de l’os, ont fait l’objet de nombreuses études au niveau individuel, en relation avec le risque de fracture ostéoporotique, mais la corrélation et les responsabilités relatives des facteurs génétiques et environnementaux entre les paires de ces trois phénotypes sont encore peu connues.

Objectif: L’étude porte sur la corrélation génétique (ρ_G), environnementale (ρ_E) et phénotypique (ρ_p) entre DMO, CMO et taille de l’os.

Sujets et méthodes: Des analyses bivariées de décomposition de la variance ont été effectuées sur 904 sujets de 287 familles nucléaires chinoises.

Résultats: Des ρ_G, ρ_E, ρ_p ont été détectées entre DMO, CMO et taille de l’os, à l’exception de ρ_E entre DMO et taille de l’os à la hanche (ρ_E?=?0,121, p?=?0,361). Des facteurs génétiques communs expliquent respectivement 86,1% et 60% des variations génétiques de DMO et CMO du rachis et de la hanche. Les corrélations génétiques et environnementales entre DMO et taille de l’os sont cependant limitées. Les ρ_G, ρ_E, au rachis sont respectivement 0,392 et 0,381 et sont 0,121 et -0,205 à la hanche. Seulement 14,5% et 4,2% des variations entre DMO et taille de l’os au rachis et à la hanche peuvent être dus à des facteurs génétiques communs.

Conclusion: Les résultats suggèrent que par suite des corrélations limitées qui lient la DMO et la taille de l’os, cette dernière peut être utilisée comme phénotype de substitution, indépendamment de la DMO, pour l’élucidation de la pathogenèse de l’ostéoporose.

Zusammenfassung. Hintergrund: Knochendichte (bone mineral density, BMD), Knochenkalkgehalt (bone mineral content, BMC), und Knochengröße (bone size) sind als bedeutsame individuelle Risikofaktoren für osteoporotische Frakturen umfangreich untersucht worden, aber es ist wenig über die Korrelation und das Ausmaß der beteiligten genetischen und Umwelt-Faktoren zwischen jeweils zwei der drei phänotypischen Parameter bekannt.

Ziel: Die Studie untersucht die genetische Korrelation (ρ_G), die umweltbedingte Korrelation (ρ_E) und die phänotypische Korrelation (ρ_P) zwischen BMD, BMC and Knochengröße.

Probanden und Methoden: Bivariate Varianz-Dekompositionsanalysen wurden bei 904 Probanden aus 287 Chinesischen Kernfamilien untersucht.

Ergebnisse: Signifikante ρ_E, ρ_G and ρ_P wurden zwischen BMD, BMC und Knochengröße entdeckt, mit Ausnahme von ρ_E zwischen BMD und Knochengröße im Hüftbereich (ρ_E?=?0,121, p?=?0,361). Gemeinsame genetische Faktoren erklärten jeweils 86,1% und 60% der genetischen Variation von BMD und BMC an Wirbelsäule und Hüfte. Allerdings waren die genetischen und umweltbedingten Korrelationen zwischen BMD und Knochengröße gering. ρ_E und ρ_G an der Wirbelsäule waren 0,392 und 0,381, und an der Hüfte jeweils 0,121 und –0,205. Nur 14,5% und 4,2% der Variation zwischen BMD und Knochengröße im Bereich von Wirbelsäule und Hüfte könnten durch gemeinsame genetische Faktoren bedingt sein.

Zusammenfassung: Die dargestellten Ergebnisse legten nahe, dass Knochengröße möglicherweise ein weiterer Ersatzparameter ist, der, wegen der begrenzten Korrelation zwischen BMD und Knochengröße, unabhängig vom BMD genutzt werden könnte, um die Pathogenese der Osteoporose aufzuklären.

Resumen. Antecedentes: La densidad mineral ósea (DMO), el contenido mineral del hueso (CMH) y el tamaño del hueso han sido ampliamente estudiados de manera individual como importantes factores de riesgo de fractura osteoporótica, pero se conoce poco acerca de la correlación y del grado en que se comparten los factores genéticos y ambientales entre estos tres fenotipos, considerados dos a dos.

Objetivo: El estudio investigó la correlación genética (ρ_G), la correlación ambiental (ρ_E) y la correlación fenotípica (ρ_P), entre la DMO, el CMH y el tamaño del hueso.

Sujetos y métodos: Se realizaron análisis bivariados de descomposición de la varianza en 904 sujetos de 287 familias nucleares chinas.

Resultados: Se detectaron significativas ρ_E, ρ_G y ρ_P entre la DMO, el CMH y el tamaño óseo, excepto para la ρ_E entre la DMO y el tamaño óseo en la cadera (ρ_E=0,121, p=0,361). Los factores genéticos comunes compartidos explicaban el 86,1% y el 60% de la DMO y las variaciones genéticas del CMH en la espina dorsal y la cadera, respectivamente. Sin embargo, las correlaciones genéticas y ambientales entre la DMO y el tamaño del hueso fueron limitadas. Las ρ_E y ρ_G en la espina dorsal fueron de 0,392 y 0,381, y en la cadera de 0,121 y -0,205, respectivamente. Sólo el 14,5% y el 4,2% de las variaciones entre la DMO y el tamaño del hueso en la espina dorsal y la cadera podían ser debidas a los factores genéticos compartidos.

Conclusión: Los resultados sugieren que el tamaño del hueso puede utilizarse como otro fenotipo sustitutivo, con independencia de la DMO, en el eventual esclarecimiento de la patogénesis de la osteoporosis, debido a las limitadas correlaciones entre la DMO y el tamaño del hueso.     

The effects of body mass index and age on cross‐sectional properties of the femoral neck

Research on the relationship between body mass index (BMI) and cross‐sectional geometry of long bone diaphyses demonstrates that strength properties are significantly greater in obese versus normal BMI individuals. However, articular dimensions do not differ appreciably. If femoral head size remains constant, we hypothesize that the femoral neck remodels to accommodate greater loads associated with increased BMI. High‐resolution CT scans (n = 170 males) were divided into three BMI groups (normal, overweight, and obese) and two age groups (21–50 and >50). OsiriX software was used to obtain a cross‐sectional slice at the waist of the femoral neck. Cortical area (CA), total cross‐sectional area (TA), percent cortical area (%CA), circularity index (I_max/I_min), section modulus (Z_pol), and second moment of area (J) were measured with ImageJ software. The effects of age and BMI were evaluated statistically. Pairwise comparisons in the younger group only detected significant differences between normal and obese males in the circularity index (P = 0.022). The older cohort showed significant differences in CA (P < 0.001), %CA (P = 0.004), Z_pol (P = 0.007), and J (P < 0.001) between normal and obese groups. This study shows that the effects of obesity on the cross‐sectional geometry of the femoral neck are more pronounced in older males relative to younger males. Older males with increased BMI have greater cortical area and bone strength in the femoral neck relative to younger males, thus making the femoral neck less susceptible to fractures in obese individuals. Clin. Anat. 28:1048–1057, 2015. © 2015 Wiley Periodicals, Inc.     

Multifactorial analysis of risk factors for reduced bone mineral density among postmenopausal women

Introduction

The study aimed to determine the risk factors for reduced bone mineral density (BMD) among postmenopausal women.

Material and methods

Two hundred and fifty-three postmenopausal women were included to the study. The study group consisted of 85 women with osteoporosis (mean age: 59.9 years) and 168 with osteopenia (mean age: 57.8 years). Patients were assigned to groups according to their BMD measured in the lumbar spine, hip and femoral neck by dual X-ray absorptiometry. Bone formation was assessed by measuring serum osteocalcin and bone resorption by measuring serum C-terminal type I α-collagen chain telopeptide.

Results

Multiple regression analysis for lumbar spine showed association of age (p = 0.001), parental history of fracture (p = 0.05), use of hormone replacement therapy (p = 0.034), bisphosphonates therapy (p < 0.001), calcium and vitamin D supplements therapy (p = 0.001), oestradiol level (p = 0.007) and body mass index (p < 0.001). Multiple regression analysis for femoral neck and hip total showed association of age (p = 0.001), parental history of fracture (p = 0.049), use of bisphosphonates (p < 0.03)) use of calcium and vitamin D supplements (p = 0.039), oestradiol level (p = 0.047). All the variables together explain 40.4% of variance in BMD for the lumbar spine and 25.6% of variance in BMD for femoral neck and hip total.

Conclusions

The present study demonstrated correlations between the variables and BMD, which are known and widely described in the literature. Osteoporosis and osteopenia in Polish subjects appear to be associated with several known risk factors that are well described in the literature.     

Relation between obesity and bone mineral density and vertebral fractures in Korean postmenopausal women

Purpose

The traditional belief that obesity is protective against osteoporosis has been questioned. Recent epidemiologic studies show that body fat itself may be a risk factor for osteoporosis and bone fractures. Accumulating evidence suggests that metabolic syndrome and the individual components of metabolic syndrome such as hypertension, increased triglycerides, and reduced high-density lipoprotein cholesterol are also risk factors for low bone mineral density. Using a cross sectional study design, we evaluated the associations between obesity or metabolic syndrome and bone mineral density (BMD) or vertebral fracture.

Materials and Methods

A total of 907 postmenopausal healthy female subjects, aged 60-79 years, were recruited from woman hospitals in Seoul, South Korea. BMD, vetebral fracture, bone markers, and body composition including body weight, body mass index (BMI), percentage body fat, and waist circumference were measured.

Results

After adjusting for age, smoking status, alcohol consumption, total calcium intake, and total energy intake, waist circumference was negatively related to BMD of all sites (lumbar BMD p = 0.037, all sites of femur BMD p < 0.001) whereas body weight was still positively related to BMD of all sites (p < 0.001). Percentage body fat and waist circumference were much higher in the fracture group than the non-fracture group (p = 0.0383, 0.082 respectively). Serum glucose levels were postively correlated to lumbar BMD (p = 0.016), femoral neck BMD (p = 0.0335), and femoral trochanter BMD (p = 0.0082). Serum high density lipoprotein cholesterol (HDLC) was positively related to femoral trochanter BMD (p = 0.0366) and was lower in the control group than the fracture group (p = 0.011).

Conclusion

In contrast to the effect favorable body weight on bone mineral density, high percentage body fat and waist circumference are related to low BMD and a vertebral fracture. Some components of metabolic syndrome were related to BMD and a vertebral fracture.     

Fat mass and fat-free mass as indicators of body composition among Bengalee Muslim children

Background: The composition of fat mass (FM) and fat-free mass (FFM) are now considered to be important indicators of body composition.

Aim: This cross-sectional study determines the body composition using FM and FFM among children.

Subjects and methods: The study was conducted among 1248 children (619 boys; 629 girls) aged 5–12 years and belonging to the Bengalee Muslim population of West Bengal, India. Anthropometric measurements of height, weight, triceps and sub-scapular skin-folds were recorded and body mass index (BMI) calculated. Body composition was assessed using FM and FFM.

Results: The age-specific mean values of FM and FFM ranged from 1.93–3.07 kg (boys) and 1.91–3.62 kg (girls) and from 14.69–23.44 kg (boys) and 14.18–22.87 kg (girls), respectively. Statistically significant sex differences were observed in FM and FFM (p < 0.05). Age- and sex-specific smooth percentile curves were derived for BMI, FM and FFM using the L, M and S modelling approach for further evaluation of body composition.

Conclusion: These findings are important for future investigations in the field and in epidemiological and clinical settings so as to accurately identify risk of lower or higher adiposity and body composition using FM and FFM.     

Response rates to oestrogen treatment in perimenopausal women: 5-year data from the Danish Osteoporosis Prevention Study (DOPS)

OBJECTIVE: To characterise women with no response or with a good response to hormone replacement therapy (HRT), evaluated by change in bone mineral density (BMD). Design: Nested case-control study within a comprehensive cohort study. SUBJECTS AND METHODS: In the Danish Osteoporosis Prevention Study (DOPS), perimenopausal women were allocated to either HRT or no HRT. In the present study, we included 466 women who had been treated with HRT for 5 years and 466 untreated women from the same cohort. Non-responders were women in the treatment group, who decreased in BMD more than the mean decrease observed in the untreated group. Good responders were women with a larger increase in BMD than the upper 95% percentile of untreated women. Baseline characteristics were evaluated as predictors of response to HRT. RESULTS: 8.4 and 5.6% were classified as non-responders, whereas 25 and 57% were good responders according to changes in BMD of the femoral neck and lumbar spine, respectively. Combining measuring sites, 2.6% were non-responders and 20% were good responders. Non-responders at the femoral neck were more often smokers and had a lower spine BMD. Good responders were older, had a higher body weight, and higher alcohol consumption. In addition, good responders at both measurements sites had a lower BMD at the total hip. CONCLUSION: A favourable BMD response to HRT can be expected in most post-menopausal women especially if they are non-smokers with a moderate--as opposed to low--alcohol intake, a high body mass and a low initial hip BMD.     

Influence of Ovariectomy on Bone Turnover and Trabecular Bone Mass in Mature Cynomolgus Monkeys

Purpose

To examine the influence of ovariectomy (OVX) on bone turnover and trabecular bone mass at the 3 clinically important skeletal sites in mature cynomolgus monkeys.

Materials and Methods

Six female cynomolgus monkeys, aged 17-21 years, were randomized into 2 groups by the stratified weight: the OVX and sham-operation groups (n = 3 in each group). The experimental period was 16 months. Lumbar bone mineral density (BMD) in vivo and serum and urinary bone turnover markers were longitudinally measured, and peripheral quantitative computed tomographic and bone histomorphometric analyses were performed on trabecular bone of the lumbar vertebra, femoral neck, and distal radius at the end of the experiment.

Results

OVX induced in a reduction in lumbar BMD compared with the sham controls and the baseline, as a result of increased serum levels of bone-specific alkaline phosphatase and urinary levels of cross-lined N- and C-terminal telopeptides of type I collagen. Furthermore, OVX induced reductions in trabecular volumetric BMD and trabecular bone mass compared with the sham controls, with increased bone formation rate at the lumbar vertebra, femoral neck, and distal radius.

Conclusion

The results indicated that OVX in mature cynomolgus monkeys (17-21 years of age) increased bone turnover and induced trabecular bone loss at the three skeletal sites compared with the sham controls. Thus, mature cynomolgus monkeys could be utilized for preclinical studies to examine the effects of interventions on bone turnover and trabecular bone mass at the 3 clinically important skeletal sites.     

Profiles of musculoskeletal development in limbs of college Olympic weightlifters and wrestlers

To investigate the event-related profiles of musculoskeletal development in weight-categorized athletes, we measured the cross-sectional areas (CSA) of bone and muscle in the forearm, upper arm, lower leg and thigh, using a B-mode ultrasound apparatus, in college Olympic weightlifters (OWL, n?=?19) and wrestlers (WR, n?=?17) and untrained men (UM, n?=?24), whose body masses were within the range from 55?kg to 78?kg. Both bone and muscle CSA at all sites were significantly correlated to the two-thirds power of fat-free mass (FFM^2/3) with correlation coefficients of 0.430–0.741 (P?P?r?=?0.664–0.829, P?2/3, both OWL and WR showed significantly greater values than UM at all sites except for the lower leg. Furthermore, the comparison of the lean (bone?+?muscle) CSA ratio from site to site indicated a higher distribution of lean tissues in the upper extremities in OWL and WR compared to UM. While there was no significant difference between the two athlete groups in FFM^2/3, OWL showed significantly larger values than WR in the bone CSA of the upper arm and thigh and in the muscle CSA of the lower leg and thigh. However, lean CSA ratios of the upper extremities to the lower ones were significantly higher in WR than in OWL. Thus, the present results indicated that, compared to UM, OWL and WR had a greater lean tissue CSA in limbs, especially in the upper extremities, even when the difference in FFM was normalized. Moreover, the relative distribution of lean tissues in limbs differed between the two weight-categorized athletes in spite of there being no difference in FFM, which may be attributable to their own training regimens and/or competition style.